Mobile wireless customizable health and condition monitor

ABSTRACT

A wearable sensor may be provided. The wearable sensor may include a timing mechanism; a plurality of sensor pairs coupled to the timing mechanism wherein each sensor pair comprises an emitter and a detector; and a microcontroller coupled in communication to the timing mechanism and the plurality of sensor pairs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/371,071, filed Mar. 9, 2006, and entitled MOBILE WIRELESSCUSTOMIZABLE HEALTH AND CONDITION MONITOR, which claims priority under35 U.S.C §119 to U.S. Patent Provisional Application No. 60/660,342,filed Mar. 11, 2005. The disclosures of the above-referencedapplications are incorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

Nursing homes and assisted care facilities employ a number of differentmethods and devices to monitor their patients. These devices are capableof monitoring physiological functions, but are generally used inisolation and not integrated with other devices. Some devices includefall alert buttons that require a patient to actively push a button toalert the staff of a care facility of a fall. This type of device,however, is not effective for a patient who has a cognitive impairment(such as dementia) is knocked unconscious or otherwise renderedincapacitated by a fall or other medical condition. Care facilities alsouse a variety of pressure pads and other sensors to provide an audiblealert to indicate that a patient has left a desired location. Thesetypes of devices have reliability problems and require a high level ofvigilance to constantly monitor the sensors. Moreover, none of thesedevices is capable of delivering private, targeted and configurablealerts for designated caregivers, nor do they provide centralized datacollection for automatic charting and close monitoring of individualpatients.

In addition to the above, many care facilities try to perform at leastsome vital sign monitoring. This may be limited to checking a patient'svital signs only once a week due to the time and cost required to havestaff to perform these duties. However, when a patient's vital signs arechecked only once a week, the declining health of a patient may only bedetected after a health condition has worsened, eliminating theopportunity for early intervention. Thus, there can be an increase in acare facility's patient morbidity and mortality rate. Additionally,staff turnover and productivity can be an issue in care facilities thatmay need to spend more time replacing and training staff members tomonitor sensors and patients' vital signs and to understand thepatient's medical history and specific need for care.

Care facilities also have an interest in knowing the location of theirpatients at their facility, as well as patients that may be locatedremotely or living at individual homes and receiving care remotely.However, typical methods of monitoring patients and determining theirlocations involve the use of video cameras and closed-circuittelevision. Another method is the use of motion detectors to infermovement and activity level within a home. These systems typicallyrequire significant wiring or installation of equipment within a homeand can be uneconomical for either home or multi-patient facility use.Moreover, motion detectors cannot distinguish between multiple residentsor pets present in the home. Additionally, this may only provide aninference, but not a direct and objective indication, of the patient'swell-being. Further, video-based services require a high level ofattention to the video feeds from the cameras and the identity of thepeople can be difficult to discern. There are additional issues inpersonal privacy and intrusion when using video or even motiondetectors. Additionally, it is not usually practical to have cameras ora video monitoring system in the house of a remotely located patient.

Other facilities, such as hospitals, have also utilized patient andpersonnel tracking systems using radio frequency identification (RFID)badges. These devices can be worn by a person and may be passive devicesor may transmit an RF signal that may be tracked from a centralizedlocation in the facility. These devices, however, do not provide anyother information besides the location of the wearer and they may notprovide adequate transmission range. Also, RFID is limited in its memoryso very little processing is available and there is no 2-way processingof event monitoring data. Other information that a care facility maydesire to collect, such as a patient's vital signs, are not collected ortransmitted by these devices. Additionally, the battery life on thesedevices can vary significantly depending on the type of RF signaltransmitted and the amount and duration of transmissions from thedevice. Typically the devices only have a battery life of a few hours orseveral days before they require recharging or replacing the batteries.Other devices designed to transmit a signal having information about apatient may utilize cellular phone technology. These devices, however,often fail to get an appropriate cellular signal inside health carefacilities and again require significantly more power and have a batterylife of hours thereby rendering such devices impractical for long-termmonitoring.

Yet other devices that have been used in battery-powered sensors includethose using IEEE 802.15.1 Bluetooth wireless technology to replacecables. Enabling devices with Bluetooth does not in itself bring aboutan integration of separate monitoring devices for one patient. Indeed,there can be a limit of eight devices that may be joined together in aBluetooth pico-net raising the question about scaling and the capacityto support hundreds of patients in a facility. The short range,typically on the order of ten meters, calls for a multimode extensivenetwork strategy to support a healthcare facility, such as a mesh orpartial mesh network, would provide for adequate coverage but alsoexceeds the specifications of Bluetooth. Merely replacing a cable from amonitor to a wireless Bluetooth-enabled equivalent can result in rapidbattery depletion if continuous monitoring is attempted.

Still other devices have been used for monitoring an individual's vitalsigns. These devices have been wearable and typically were capable ofmonitoring some vital signs, such as pulse rate and body temperature.These devices, however, typically only have the ability to display theinformation collected on a display that is either worn on the individualor on separate display that the collected data is downloaded onto. Somedevices that monitor vital signs, such as pulse rate, require thepatient to be relatively still to obtain an accurate reading. Otherdevices have included the ability to transmit location information totrack the movement of an individual. These devices, however, do not havethe ability to transmit collected data on the individual back to acentral location for analysis. Further, these devices usually require aperson to wear a variety of different sensors and can be intrusive onthe person, embarrassing to wear, and prohibit some movement. Thesedevices also only allow a person to wear the device for a limited time,for example a few hours to several days, before the power source must bereplaced or recharged.

Therefore, a need exists for a system that can track and monitor apatient using a wearable, form-friendly, low-power, wireless device thatcan be used to monitor the health and wellness of a person wearing thedevice during the person's daily activities, over long periods of timewithout the need to recharge the device, and without the constantsurveillance of healthcare personnel.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary embodiment, a wearable sensor may be provided. Thewearable sensor may include a timing mechanism; a plurality of sensorpairs coupled to the timing mechanism wherein each sensor pair comprisesan emitter and a detector; and a microcontroller coupled incommunication to the timing mechanism and the plurality of sensor pairs.

In another exemplary embodiment, a monitoring system may be provided.The monitoring system may include at least one wearable monitor coupledto a user, the at least one wearable monitor may include a timingmechanism; a plurality of sensor pairs coupled to the timing mechanismwherein each sensor pair comprises an emitter and a detector; and amicrocontroller coupled in communication to the timing mechanism and theplurality of sensor pairs; at least one gateway having a secondtransceiver; at least one device located at a remote location; and atleast one server coupled in communication using a wide area network tothe at least one gateway and the at least one device, the at least onewearable monitor is coupled in wireless communication to the at leastone gateway, the plurality of sensor pairs facilitate sensing a heartrate of the user and transmit the heart rate to the at least one server.

In yet another exemplary embodiment, a method may be provided of sensinga heart rate using a wearable monitor that includes a timing mechanism,a memory, a plurality of sensor pairs coupled to the timing mechanismwherein each sensor pair includes an emitter and a detector, and amicrocontroller coupled in communication to the timing mechanism, thememory and the plurality of sensor pairs. The method may includecoupling the wearable monitor to a user; emitting an electromagneticwave from the emitter into the user; receiving an electromagnetic wavesignal from the user at the detector; stabilizing the electromagneticwave; determining a first pulse; determining a plurality of subsequentpulses; calculating a heart rate of the user; and recording the heartrate of the user in at least one server.

In yet another exemplary embodiment, a health care monitoring system maybe provided. The health care monitoring system may include means foremitting electromagnetic waves into a user; means for receiving theemitted electromagnetic waves as a signal; means for determining aplurality of peak amplitudes within the signal; means for calculating aheart rate of the user; and means for recording the heart rate on atleast one server.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of embodiments of the present invention will be apparent fromthe following detailed description of the exemplary embodiments. Thefollowing detailed description should be considered in conjunction withthe accompanying figures in which:

FIG. 1 shows an exemplary diagram of a health care monitoring system;

FIG. 1 a shows an exemplary diagram of a health care monitoring system;

FIG. 2 shows an exemplary diagram of a wearable monitor;

FIG. 3 shows an exemplary diagram of a repeater;

FIG. 4 shows an exemplary diagram of a gateway;

FIG. 5 shows an exemplary diagram of a mobile gateway;

FIG. 6 shows an exemplary diagram of a server;

FIG. 7 shows a side view of an alternative monitor that may be used withthe system shown in FIG. 1;

FIG. 8 shows a bottom view of the monitor shown in FIG. 7;

FIG. 9 shows a perspective view of a band that may be used with themonitor shown in FIG. 7;

FIG. 10 shows a chart readout of a raw signal that may be detected bysensors and analyzed by the monitor shown in FIG. 7;

FIG. 11 shows a heart rate and heart rate variability code structurethat may be used with the monitor shown in FIG. 7;

FIG. 12 shows a schematic of the monitor shown in FIG. 7;

FIG. 13 shows a heart rate and heart rate variability algorithm that maybe used with the monitor shown in FIG. 7; and

FIG. 14 shows an alternative monitor that may be used with the systemshown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention are disclosed in the followingdescription and related figures directed to specific embodiments of theinvention. Those skilled in the art will recognize that alternateembodiments may be devised without departing from the spirit or thescope of the claims. Additionally, well-known elements of exemplaryembodiments of the invention will not be described in detail or will beomitted so as not to obscure the relevant details of the invention.

As used herein, the word “exemplary” means “serving as an example,instance or illustration.” The embodiments described herein are notlimiting, but rather are exemplary only. It should be understood thatthe described embodiments are not necessarily to be construed aspreferred or advantageous over other embodiments. Moreover, the terms“embodiments of the invention”, “embodiments” or “invention” do notrequire that all embodiments of the invention include the discussedfeature, advantage or mode of operation.

Referring generally to FIGS. 1-6, a medical situation awareness systemthat can monitor the health, location or well-being of a person isshown. The system may include a user-friendly, internet-based interfaceand tools for analyzing data. The system may also include a scalable,customizable database for management and codification of the uncertainrelational knowledge gathered regarding multiple data types that may becollected about the person. This database can include advanced analytictools. Additionally, the system can include a Bayesian advanced analyticsoftware tool that can take the uncertain relational knowledge gatheredand develop a Bayesian relational network. This network may then be usedto create a predictive model of medical condition for the monitoredpatient. The model may be used, for example, to filter false positives,incorrect data or inaccurate data. This may be accomplished by includingother data types that correlate in a health model. This autonomicprocess could allow for an effective wearable monitoring system becausethe event data from the sensors could require significant analysis timeby an operator to ensure an accurate picture of the patient's overallhealth is provided. Further, the system may have a graphical interfacethat can be used for results analysis or health care suggestions. Thissystem may be employed in any of a variety of situations, for examplehospitals, extended care facilities, nursing homes, private homes, orany other situation where it is desirable to monitor and provide carefor a person.

FIG. 1 shows an embodiment of a health care monitoring system. System100 may have a variety of components, such as monitor 102, gateway 106and server 110. Monitor 102, gateway 106, and server 110 may transmitdata to each other and receive data from each other through any of avariety of wireless transmission protocols. Further, monitor 102 mayinclude sensors 114 to detect physiological, locational and other datafrom a wearer of monitor 102. These sensors may include, but are notlimited to a temperature sensor, a pulse oximetry sensor, a variety ofbody sensors, a fall detection sensor, and a location sensor, as well asany of a variety of other sensors. Additionally, external sensor 112 maybe disposed separately from sensors 114 to detect and transmit data froma location apart from monitor 102. Monitor 102 may further includeprocessing and storage capabilities 116 for processing and storing thedata from the sensors as well as data received from outside sources.Monitor 102 may also include display 117 for facilitating communicationto the patient of patient reminders and messages from server 110 orgateway 106. Also, mesh network 118 may be utilized with monitor 102.Mesh network 118 may include a variety of repeaters so as to allow forthe transmission of data over significant areas as well as for use inproviding location information of a wearer of monitor 102.

Gateway 106 can communicate wirelessly with monitor 102 and server 110and may also include processing and storage capabilities 120, which maybe able to process and store data transmitted from monitor 102, as wellas data generated by gateway 106 and data received from server 110.Gateway 106 may be part of a wireless local area network (LAN) 122 andalso part of other networks 124, allowing it to communicate with otherdevices, for example, over the Internet.

Server 110 may communicate with gateway 106 over network 130 to bothsend and receive data. Server 110 may include processing and storagecapabilities 128, which may be used for processing, interpreting andstoring data received from gateway 106 and monitor 102, as well asperforming other analyses, such as eliminating false alarms andpredicting future events. Further, server 110 can include a display 126,such as a nurse's display, where a person may access the data stored andprocessed by server 110.

In another embodiment shown in FIG. 1 a, a system 100 for monitoring thehealth, location or well-being of a person is shown. Here, a person mayuse a device such as a wearable monitor 102. The monitor 102 can be ahardware device taking the form of an arm band or a wrist band or adevice that can be applied to the skin via a bandage, as a non-limitingexample. In a further embodiment, the monitor 102 can be wearable andnot interfere with any range of motion or actions of a person. Thedimensions of the monitor 102 may also be small, for example, 1″×1″×3″or smaller. There may be a variety of sensors, such as a pulse sensor,temperature sensor and a mobility sensor, integrated into the monitor102, as a few non-limiting examples. Further, a panic button may bedisposed on the monitor 102, allowing a wearer or other person to send asignal to a remotely located party, such as a caregiver or a facility'sserver. Additionally, the monitor 102 may incorporate “fall detection,”which can detect if a person falls down or otherwise moves in a mannerthat could result in an injury. The fall detection may use any of avariety of sensors, alone or in combination, for example,piezoelectric-based, accelerometer-based and gyroscopic-based. Thesensor or sensors may be incorporated in the monitor 102 whether it isworn on a wrist of a patient or anywhere else on their body. Further,the fall detection portion of the monitor 102 can send also send asignal to a caregiver or a facility's server.

In an additional embodiment of the monitoring system, the wearablemonitor 102 can send a wireless signal to a repeater 104. The repeater104 can be a custom hardware device that may be battery or AC powered.The repeater 104 may also be installed in any location where additionalrouting nodes may be required, to provide further wireless coverage andallowing the wearable monitor to communicate with a smart gateway.

Further, in the system shown in FIG. 1 a, a smart gateway 106 may beutilized to further transmit a wireless signal. In one exemplaryembodiment, the smart gateway 106 may be a hardware device thatintegrates IEEE 802.15.4 ZigBee wireless networking components withEthernet, 802.11 wireless routers or a modem. IEEE 802.15.4 may be usedas it allows a large number of nodes to join the network, thuspermitting a large number of patients to be monitored. Communication mayoccur over the 2.4 GHZ band, which is unlicensed and available in mostlocations, allowing for a single product to be utilized throughout theworld. Additionally, to avoid congestion caused by other devices usingthis band, the IEEE 802.15.4 ZigBee standard may use 16 channels in the2.4 GHz band, allowing the monitor 102 to utilize less crowded channelswhen necessary. Likewise, any spectrum, which may be licensed for thepurpose of monitoring or may be not licensed, such as the 5 GHzspectrum, may be used to avoid potential interference with otherdevices. Also, because 802.15.4 has a relatively long range, largerscale monitoring can occur. This transmission protocol is also a verylow power protocol, allowing for extended use of the monitors, and thelow data rate and limited interference with other devices allow for802.15.4 devices to work in environments where other RF devices arealready operating. However, in other exemplary embodiments, any othertype of wireless networking devices, components or protocols may usedwith the gateway 106. The gateway 106 can collect the event datagenerated by the wearable monitor and may send real-time medical alertsdirectly to a caregiver or, alternatively, to a facility's server forfurther analysis and action.

Although the above embodiments discuss the IEEE 802.15.4 ZigBee wirelessstandard, any wireless communication protocol known by a person ofordinary skill in the art could be used for transmitting and receiving.In another embodiment, any wireless communication protocol known to aperson having ordinary skill in the art that has economical powerconsumption, reasonable data rates, limited interferences, andsufficient range may be used.

After the wireless signal shown in FIG. 1 a is transmitted from thesmart gateway 106, it can pass through a local area network 108 to aserver 110. The server 110 can be a software application that allows anursing home facility or other care giving facility to track theincidence of fall reports, medical emergencies and other transmissionsof the wearable monitor at their site. The server 110 can also have theability to send targeted real-time medical alerts to facility employeesand can escalate these alerts to various members on the staff, as wellas track response times, for example, to the medical alerts. The server110 may also provide statistics on the vital signs of the residents aswell as the location of the residents. Further, the server 110 may beable to perform intelligent analyses of event data, and of multiplecorrelating data types in health models created by the system, tominimize false alarms and allow for predictive decision support ofhealthcare providers, which could lead to improved care. Datatransmitted to the server 110 may be forwarded to any of a variety ofdevices 112, and be viewable over the Internet or a local area network.The data may then be reviewed and analyzed by an authorized person atthe remote location of the device 112.

In yet another embodiment, the system 100 may be used in either a healthcare facility or at an individual's home. Further, a monitor 102 thatfunctions in a health-care facility may also change locations to theindividual's home or another location that is compatible with thesystem. Additionally, if the user moves back to the original carefacility, the monitor 102 can continue to work seamlessly. Further, thesame equipment for system 100 that is used in a health-care facility maybe used for a patient at their home, as the equipment is typicallyrelatively inexpensive. The message protocols used in the system canprovide end-to-end integrity and security in the data from each wearablemonitor and each sensor as the data is transmitted over wirelessnetworks to the Internet or public carrier networks to reach the serverhaving patient's records.

FIG. 2 shows a more detailed diagram of the wearable monitor 102. Themonitor 102 may be used to monitor the health and mobility of thewearer. In one embodiment, the monitor 102 may be a low-cost, highvolume device that can be replaceable if it is lost or broken. Themonitor 102 may also be customized based on whether or not it is beingused in a wearer's home or at a care facility. The monitor 102 caninclude a wristband device, which may be a physically attractive,compact device capable of being worn on the wrist, similar to a wristwatch. Alternatively, the wearable monitor 102 may be a pager-sizeddevice that can be attached to the belt of a wearer or to an armband orleg-band on the wearer. In yet another embodiment, the wearable monitor102 could be formed so that it is integrated in a bandage or similaradhesive device that may be securely worn anywhere on the body of awearer.

Although some embodiments have been described as including a wrist watchor pager-sized device, or the same divided into two or more smallerpieces, or any configuration known to one having ordinary skill in theart that would attach to the body securely and not inhibit or intrudeupon the mobility, nor limit the range of motion of a user may be used.A version of the wearable monitor called a “wand” may be carried byauthorized healthcare and support personnel. The wand can function tocommunicate with the server or other system components to verify patientidentity, verify proper operation of the patient's wearable monitor,verify that the healthcare personnel have responded to medical alertsand notifications made by the system and have attended to the needs ofthe patient, as well as verify or determine any other relevantinformation.

The monitor 102 may have a variety of internal components, regardless ofwhether the wearer has the wristband device or the pager-sized device.An 802.15.4 wireless transceiver 202 may be disposed in the monitor.Alternatively, another wireless transceiver may be used with monitor102. Additionally, an antenna can be disposed in the device. The antennamay be able to produce a significantly uniform signal having asignificantly uniform signal strength emanating to all directions(substantially isotropic) regardless of the orientation of the monitordue to change in position of the wearer of the monitor. The antenna mayfurther be optimized for communication in an indoor environment. Aprocessor 204 may also be housed in the device. In an exemplaryembodiment, the processor 204 can be an ultra-low power 8-bit processor.Additionally, a processor 204 may be utilized that has a hibernate modewhere only micro-amps of current are used to power the hibernatingdevice, and which only “wakes up” or activates to process events whichcan minimize power requirements and extend battery life. Flash memory(not pictured), or any type of solid-state memory known to one havingordinary skill in the art, may also be employed in the monitor 102. Theflash memory can contain the latest sensor data and alerts when thewearable monitor is out of the range of a network, the protocol stack aswell as firmware developed to react to events generated by the sensors.

In addition, the monitor can include any of a variety of sensors. Thesesensors can include medical-grade sensors which can be employed todetermine the health of the wearer. For example, the sensors may includea pulse sensor 206, a temperature sensor 208 and accelerometers for thex-y axis 210 and z axis 212, allowing for mobility detection and falldetection. Further the mobile device can include a battery or batteries214. The battery or batteries 214 may be such that they allow for thedevice to run off of the battery power for more than six months. Any ofa variety of batteries may be used in both the wristband and pager-sizeapplications. The battery or batteries 214 may also be any of a varietyof rechargeable batteries, and may therefore reduce the need forreplacing battery or batteries 214.

Further embodiments of the monitor 102 not pictured in FIG. 2 mayinclude a blood pressure sensor, a pulse oximetry sensor (to providemore accurate blood oxygen saturation determination mechanisms), atemperature sensor, respiratory rate sensor, wireless network-basedlocation sensor and GPS or cell-based geo-location and E911 service.Further embodiments of the monitor 102 not pictured in FIG. 2 mayinclude sensors for military, hazardous or similar applications, forexample a blast pressure sensor or a bio-contagion sensor. Individualsensors may be utilized to monitor these events or a single sensor maybe utilized to perform a one or more of the tasks. Additionally, a shockmeter that may use galvanic skin resistance and skin temperature, alongwith event analysis software to provide an early detection of shock maybe incorporated.

Although the above preferred embodiments discuss a blood pressuresensor, laser pulse oximetry sensor, a temperature sensor, respiratorysensor, GPS and E911 services, any other sensor or service known to onehaving ordinary skill in the art may be used or incorporated into thedevice.

The wearable monitor 102 can use wireless networking components in orderto send vital sign data, location information and medical emergencyalerts. In one exemplary embodiment, 802.15.4 ZigBee wireless networkingcomponents (e.g. transceiver 202) may be used. In another exemplaryembodiment, any other wireless networking components may be used thatmay be disposed on monitor 102 and provide for transmitting andreceiving data wirelessly. Additionally, the monitor 102 can incorporateGPS locating capability to provide detailed location information of thewearer. Further, a cellular modem may be incorporated onto the monitor102, allowing the wearer to be monitored from remote locations and,optionally, interacting with ZigBee or equivalent-enabled mobile phones.

The software that can be used in the wearable monitor 102 can bedesigned to be small, thus limiting the amount of processing powerrequired and therefore extending battery life. Additionally, thesoftware incorporated on the monitor 102 can be programmed intofirmware. One portion of the software can include an IEEE802.15.4/ZigBee protocol stack or any alternative wireless protocolstack. This combination can provide the ability for the wearable monitor102 to wirelessly communicate with one or more repeaters and gateways.Additionally, in one embodiment, since the wearable monitor 102 mayrequire very low power consumption, it can be considered an end nodethat does not route data, and thus may be considered a reduced functiondevice (RFD) under the IEEE 802.15.4 standard. However, in otherembodiments, the monitor 102 can have full routing functions and utilizeany known wireless standard. Further, the software may also be able torespond to beacons or directed messages from a gateway device that isrequesting current sensor data to be sent. Also, in a furtherembodiment, the data transmitted from the wearable monitor 102 can beencrypted, for example, using the security capabilities of the 802.15.4standard or any other Advanced Encryption Standard (i.e. AES 128 or AES256) scheme known to one of ordinary skill in the art may be used.

Additional software may be used for processing sensor data and ensuringthat out of range data is processed for all of the sensors that areintegrated into the device. For example, in the case of fall detection,the software should be able to process the data and determine if a fallhas occurred or if a typical movement has occurred. Also, sensor datamay be time stamped, gathered and sent to a gateway on a periodic basisfor statistical tracking of norms. In a further embodiment, if there isa network failure, data or high-water mark sensor data can be latchedand transmission can be retried until transmission is confirmed.Additionally, the wearable monitor 102 can also test battery power ofbattery 214 on a regular basis and may also transmit a “low battery”alert when battery life has decreased below a predetermined amount, forexample, 20% of the remaining battery life. Alternatively, a “lowbattery” alert may be transmitted at any predetermined amount at orbelow 50% of the remaining battery life.

An exemplary repeater is shown in FIG. 3. A repeater 104 can ensure thatadequate wireless coverage is maintained across the facility or homewhere the wearer of the monitor is located. In one embodiment, arepeater 104 can collect the statistics and alerts generated by thewearable monitor 102 and transmit real-time medical alerts to acaregiver or a care facility's server. Increasing the number ofrepeaters, for example in a mesh pattern or any other pattern known byone of ordinary skill in the art that will provide the desired coverage,in a given location, can also reduce the number of gateways that a homeor facility may need. Additionally, the number of repeaters may beincreased to support a virtually unlimited number of monitored patientsand, additionally, determine the location of any individual patient.Repeaters can also compensate for the signal sent from an ultra-lowpower wearable monitor, which may have a limited transmission range. Therepeater 104 can use a variety of hardware and software and may bechanged or customized depending on the type of repeater that is beingused. Non-limiting examples of different repeaters include aninternal-use-only repeater that is A/C powered with battery backup, aninternal-use-only repeater that is D/C battery powered, a weatherproofrepeater that is A/C powered with battery backup, and a weatherproofrepeater that is D/C battery powered.

A repeater 104 may also utilize a variety of internal hardwarecomponents, as shown in FIG. 3. With the exception of the A/C powertransformer in the A/C power devices, the hardware configurations fordifferent repeaters may all be the same. The repeater can house an802.15.4 wireless transceiver 302 that meets both the size and powerrequirements of the device. The 802.15.4 transceiver 302 may be furtherintegrated with an Ethernet connection, one or more 802.11 wirelessInternet routers and one or more dial-up modems (not shown). In otherembodiments, the repeater 104 may house any other type of wirelesstransceiver. Additionally, the repeater 104 can have an antenna, whichmay be customized or altered depending on whether or not the monitor isbeing used indoors or outdoors. Further, the repeater 104 may also havean ultra-low power 8-bit processor 304, similar to the one describedabove with respect to the monitor and optionally having a hibernatemode. Additionally, the repeater 104 can utilize flash memory containingthe protocol stack as well as firmware developed to react to repeaterevents, a battery or batteries 306, which may power the repeater for oneyear or longer and an A/C power transformer 308, which can be utilizedfor locations with an electrical plug.

The repeater 104 may also have a software component designed to be smallto limit the amount of processing power and thus extending the battery306 life in the event that the device is not A/C powered. This softwaremay be entirely programmed into the firmware. One part of the softwaremay be the IEEE 802.15.4/ZigBee protocol stack, or any other appropriatewireless protocol stack, which can provide the ability for the repeaterto wirelessly communicate with wearable monitors and gateways in thesystem. The repeater 104 can be designed as a routing node, allowing itto pass data along from source nodes to destination nodes. The repeatermay also be considered a full function device (FFD) in terms of the IEEE802.15.4 standard. The repeater 104 further may utilize any of a varietyof batteries, for example type N or rechargeable batteries, to power itas it routes data or may alternatively be A/C powered. Finally, thesoftware on the repeater 104 may also respond to beacons from a gatewaydevice, which can request current status to be sent. The status datatransmitted from the repeater 104 to a gateway device can include bothstatus data of the repeater 104 itself as well as current status data ofthe wearer of the monitor 102. If the repeater 104 is battery powered,additional processing may be performed that tests the battery power on aregular basis and sends a low battery alert when a predetermined amountof battery power in battery or batteries 306 is, for example 20%.Alternatively, a “low battery” alert may be transmitted at anypredetermined amount at or below 50% of the remaining battery life.

An exemplary gateway device, as shown in FIG. 1, item 106, is shown ingreater detail in FIG. 4. The gateway device 106 can be a fixed-locationdevice that bridges a 802.15.4 ZigBee wireless network, or any otheralternative wireless network used by the above-described devices, with alocal area network in a facility or home. A variety of wearable monitors102 and repeaters 104 may operate through an individual gateway 106 andthe gateway 106 may have similar functionality to an 802.11 wirelessaccess point, or any other type of wireless access point. Similar to therepeater 104, the gateway 106 may utilize a variety of hardware andsoftware components. Additionally, the gateway 106 may have differentconfigurations based on the local area network 108 that is configured ina facility or home. For example, a gateway 106 may be an A/C powereddevice with Ethernet network connectivity, an A/C powered device with0.802.11b (or other) network connectivity, or an A/C powered device withmodem connectivity.

In a further embodiment shown in FIG. 4, a gateway 106 may have avariety of hardware components. These components may include an 802.15.4wireless transceiver 402, or any other type of wireless transceiver, andan antenna, similar to those in the repeater 104. The gateway 106 mayalso have a processor 404, for example a 32-bit processor. Additionally,the gateway 106 can utilize flash memory 406, or other memory type,which can store patient data as a temporary network buffer and containthe protocol stack as well as firmware message processing 408. Thegateway 106 can also have an amount of RAM that is needed for theapplication and an A/C power transformer 410 to provide power for thegateway, as well as an internal D/C battery backup.

The gateway 106 may also provide Internet connectivity. Connections tothe Internet may be made by at least one of an 802.11 wirelessconnection 412, Ethernet connection 414, modem 416, cellular or mobiledata service 418, or any other device capable of connecting to theInternet.

The software used in the gateway 106 shown in FIG. 4 can be used inprocessing events from the wearable monitor and may optionally beLinux-based. Additionally, all of the software incorporated into thegateway may be programmed into the firmware. One such software componentis an operating system, for example a Linux or Linux-variant operatingsystem 408. Further, the gateway 106 can include an IEEE 802.15.4/ZigBeeprotocol stack, or any other type of wireless protocol stack, thecombination of which can provide the ability for the gateway 106 towirelessly communicate with wearable monitors 102 and repeaters 104 inthe system 100. The gateway 106 may further be designed as a routingnode so that it can pass data along from source nodes to destinationnodes. The gateway 106 may be considered a personal area network (PAN)coordinator node under the terms of the IEEE 802.15.4 or master nodeunder IEEE 802.15.1 or other wireless standard. Additionally, if thereare multiple gateways in the network for scalability, a single gatewaymay be chosen as the PAN coordinator and the remaining gateways canfunction as coordinators in a cluster tree network topology. Thecoordinator nodes can also generate beacons, for example statusrequests, that the other nodes in the network may respond to on aperiodic basis.

Other software included in a gateway 106 can include a reliable queue,which can provide for scalability and reliability of the delivery ofcritical monitoring events to the server, as well as delivery ofcritical confirmations and messages from the server to monitors 102. Agateway 106 can also have the capability to process the events sent toit by the wearable monitors 102 and the repeaters 104. In situationswhere there may be multiple events from the same monitor 102 or repeater104, the gateway 106 can have the intelligence to collapse the eventsand perform a root cause analysis. Finally, gateways can receivesoftware upgrades and updates. Further, gateways may be able to upgradethe wearable monitor and repeater components when new firmware is madeavailable for updates.

In another embodiment, the system may be utilized in the home of apatient. A home-based system, however, may contain a gateway 106 havingadditional intelligence so that it also can have the decision makingcapabilities based on a patient's physiological trends and statisticaldata for instances where a patient can be provided immediate feedbackfor self awareness and patient education about their ailments. A homebased system may also contain repeaters 104 serving as locating nodesand providing daily activity assessment data regarding the patient. Thegateway device 106 may also be able to continue communication with ahealthcare provider's server 110 so that a healthcare team can maintaintheir ability to monitor the patient. The communication between thesystem in the patient's home and the healthcare facility can be securelydelivered through encryption to ensure patient privacy and, ifnecessary, to comply with the Health Insurance Portability andAccountability Act (HIPAA) regulations and, if necessary, militaryspecific requirements.

In an alternative embodiment shown in FIG. 5, a mobile gateway 500 maybe used in lieu of or with gateway 106. The mobile gateway 500 functionssimilarly to gateway 106, insofar as it can have a wireless transceiver502 and antenna, processor 504, operating system 506 and flash memory508. A mobile gateway 500 can also bridge the ZigBee wireless network,or any other wireless network used with the system, with a cellularnetwork 512 and allow for monitoring of the wearer of a monitor 102 whenthe monitor 102 is away from their home or facility. A mobile gateway500 can also contain GPS locator 510 capabilities to identify thelocation of the wearer in case of an emergency event. Further, mobilegateway 500 may use rechargeable battery 514 or an A/C source to powerthe device. A mobile gateway 500 may be configured in a variety ofmanners, such as by partnering with a mobile phone manufacturer tointegrate gateway capabilities into a ZigBee-enabled, or other wirelessprotocol-enabled, mobile phone or by integrating gateway cellular andGPS capabilities into a wearable monitor.

FIG. 6 shows a more detailed view of server 110. The server 110 canprocess the logic associated with the monitoring system 100 and providethe capability to configure the user information and handle theprocessing of events from various users using statistical analysisengine 602. Further, the server 110 can track and store the incidence offalls and other medical emergencies at the site using storage, databaseor databases, or memory 603 in conjunction with statistical analysisengine 602. It can also have the ability to send targeted real-timemedical alerts to caregivers and may optionally escalate these alerts toadditional members of a healthcare team as well as track response timesusing alert notification 604. These alerts may include email 606, voicetransmission 608, SMS 610 or other alert transmission 612. The server110 may also provide statistics on the vital signs of a patient orpatients as well as their location and, through the use of complexapplications software, can make intelligent decisions based on trends inpatient data and statistical data using tools disposed in statisticalanalysis engine 602. Server 110 may include triage sorting capabilities614, allowing for improved organization of patient data. A presentationuser interface 616 may also be used with server 110 so as to provide anaccessible and easily navigable way of viewing data in server 110 andinitiating messages that are intended for monitor 102. The presentationuser interface 616 may further be used by operating system andnetworking software 622 to provide additional methods of user access.Additionally, server 110 may have security perimeter 618, which mayprevent unauthorized access to data transmitted to the server. Networkconfiguration data, privacy information and management data 620 may alsobe housed on server 110. Finally, server 110 may also include patientdata manager 624, which may house any of a variety of data associatedwith any number of patients.

The server 110 may also include one or more databases 603. Data storedin the one or more databases 603 can include accumulated patientinformation and system configuration information. This information canbe used for a variety of purposes, such as supporting one or more remotemonitors, one or gateways, one or more repeaters, and any other devicethat may be used in the system.

In one exemplary embodiment, at least one server may be used fordeployment in support of a number of gateways, repeaters and monitors.The server, e.g. server 110, and system architecture can be flexible andscalable, however, allowing the number of servers deployed will bedetermined, for example, by the unique requirements presented byinstitutional organization, the desire by the institution for local orremote maintenance support, physical and geographic distance, networkreliability, desired separation of data among multiple institutions,processing capacity desired and any other relevant needs or desires.Processing may be distributed across multiple specialized servers, whichcan allow, for example, certain portions of the database and complexsoftware applications for statistics to be on one or more servers at onelocation, and certain portions of the database and complex softwareapplications for communications and configuration with gateways andassociated repeaters and monitors might be at another location orlocations. Some deployments may include gateways, repeaters and monitorsat one location but all of its supporting servers are at a differentlocation.

The server 110 may include software bundles with rack-mounted serverhardware included in operating system and networking software 622. Thiscan be, for example, a standard Intel-based processor and PC-likefunctionality. Further, the server 110 associated with a deployment canhave a variety of application software built on top of open sourcesoftware components. Other software components can include an operatingsystem, such as Linux, a Linux variant, Windows or a Windows-basedoperating system. A web-based interface, such as presentation interface616, can also be provided via a web server, for example Apache httpserver. Further, an application server, such as Tomcat, can be used todynamically monitor events and statistics and configure contactinformation notification services. A database may also be used topersist the configuration and data, such as patient information, contactdata, and statistics. Because multiple patients, multiple monitors andmultiple sensors may be included in the system, the configuration mayhave unique identifiers for each patient, as stored in patient datamanager 624. Additionally, a set of unique messages appropriate for eachtype of event and each type of data from a sensor may be used. Complexsoftware applications, such as engine 602, may utilize the data tocreate patient records, statistics, and analysis of data for reports.Complex software applications can also apply statistical techniques suchas Bayesian Networks, moving averages, regression analysis, inference,probabilistic reasoning, and other analytical, machine learning, andartificial intelligence techniques known to a person having ordinaryskill in the art to filter and apply data. Standard reports can beavailable on a per-event, per-patient, and per-facility basis, as wellas any other desired basis. The ability to customize reports can be madeavailable and the output from these reports could potentially also beused for billing or for quality control. Examples of open-sourcedatabase projects that may be utilized are Apache projects such asApache Derby, and mySQL or other databases known to a person havingordinary skill in the art.

The server 110 software may also include reliable queue, which canensure scalability and reliability of the delivery of criticalmonitoring events to the caregiver mobile devices. Additionally, anotification service can provide the ability to communicate with mobiledevices as well as the ability to send SMS text messages to pages andmobile phones as well as the sending of voice messages. The server 110can further have the ability to process all of the events sent to it bythe gateways in the facility or network and, additionally, the server110 can have the ability to upgrade the gateway 106 as well as providefirmware to the gateway 106, which, in turn, can upgrade the wearablemonitor 102 and repeater 104 components when new firmware, if desired,is available.

In another exemplary embodiment, server 110 may be able to identifyspecific sensor values and time stamps that originate from a specificmonitor, e.g. monitor 102. This identification may be able to take placeregardless of how the data from monitor 102 is transmitted or over whichnetwork path or paths the data is transmitted. For example, server 110may identify data as being sourced from monitor 102 despite the datagenerated by monitor 102 having traveled over one or more of a wirelessnetwork, the Internet, a private local area network (LAN), wide areanetwork (WAN), and a satellite or public carrier wired or wirelessnetwork. Additionally, server 110 may also account for data that mayhave been temporarily stored in monitor 102 when transmission was notavailable and later transmitted to server 110. The data sent from anexemplary monitor may include a protocol of identification and unique orspecific messages and formats for the exemplary monitor. The transmitteddata may include information such as values generated by sensorsdisposed on the monitor, the time of a sensor value, informationsupportive of a message error detection and correction scheme and anencryption method to protect user privacy, which may exceed HIPAAstandards.

In another embodiment, server 110 may provide notification or reportinformation on the wellness or health of a wearer of monitor 102. Server110 may provide this information by utilizing complex applicationsoftware that compares incoming data from monitor 102 with previouslystored data from monitor 102 and other monitors recording similar data.Additionally, patient responses to messages sent by server 110 anddisplayed on monitor 102 may provide additional feedback and automaticpopulating of longitudinal data in databases 603 for compilation byengine 602. The comparison of the sum of the data can be used togenerate predictive probabilistic statistics, for example probabilisticstatistics derived from multivariate Bayesian inference networks,probabilistic relations with a deterministic predictive capability forimpending events, and comparison to peers in population-based diseasemodels. The data sourced from monitor 102 may be further be encryptedand server 110 may decrypt the data prior to processing and analyzingit. This data may also be correlated to generate notificationsindicating changes in the health status of a wearer of monitor 102.Additionally, server 110 may generate location data for monitor 102based on the network interaction and signal attributes of monitor 102,such as which devices monitor 102 is transmitting to and which networkpaths data generated by monitor 102 are being transmitted over.

FIG. 7 is a side view of an alternative monitor 700 that facilitatesnon-intrusively and more continuously detecting a user's heart beat anddetermining the user's heart rate. FIG. 8 is a bottom view of monitor700. In the exemplary embodiment, monitor 700 may be a watch worn by theuser on the user's wrist. Alternatively, monitor 700 may be worn on anypart of the user's body, such as, but not limited to, a finger, anankle, a thigh, a bicep, the head, the neck or the abdomen. In anotherembodiment, monitor 700 may be any type of bracelet, anklet and/or otherwearable accessory that enables monitor 700 to function as describedherein.

In the exemplary embodiment, monitor 700 may include a casing 702coupled to a band 704 wherein a plurality of internal components may becoupled within casing 702. In one embodiment, monitor 700 may include abattery 706, an antenna 708, memory 710 and a wireless transceiver 712,which are all coupled to a processor 714. Wireless transceiver 712facilitates communicating with server 110 and/or any other communicationcomponents of system 100. Additionally, antenna 708 facilitatesproducing a significantly uniform signal having a significantly uniformstrength emanating in all directions. Antenna 708 may be furtheroptimized for communication in an indoor environment. In one embodiment,processor 714 can be an ultra-low power 8-bit processor. Moreover,processor 714 may include a hibernate mode where only micro-amps ofcurrent are used to power the hibernating device, and which only “wakesup” or activates to sample data or process events, which can minimizepower requirements and extend battery life. In one embodiment, memory710 may contain the latest sensor data and alerts when monitor 700 isout of the range of a network, the protocol stack as well as firmwaredeveloped to react to events generated by the sensors.

In the exemplary embodiment, the term “processor” is not limited to justintegrated circuits, but broadly refers to a microcontroller, amicrocomputer, a programmable gate array, a programmable logiccontroller, an application specific integrated circuit and otherprogrammable circuits. These aforementioned terms may be usedinterchangeably herein. As a result, processor 714 may be any type ofprocessor known to a person having ordinary skill in the art thatenables monitor 700 to function as described herein. In the exemplaryembodiment, processor 714 may include a bus (not shown) or othercommunication mechanism for communicating information, wherein processor714 may be coupled to the bus and facilitates processing theinformation. In one embodiment, a plurality of processors 714 may bearranged in a multi-processor arrangement to facilitate fasterprocessing as compared to a single processor arrangement. In theexemplary embodiment, memory 710 may include flash memory, random accessmemory (RAM) or other dynamic storage device (e.g., dynamic RAM (DRAM),static RAM (SRAM) and synchronous DRAM (SDRAM)) coupled to the bus forstoring information and instructions to be executed by processor 714. Inaddition, memory 710 may be used for storing temporary variables orother intermediate information during the execution of instructions byprocessor 714. Monitor 700 may further include a read only memory (ROM)or other static storage device (e.g., programmable ROM (PROM), erasablePROM (EPROM) and electrically erasable PROM (EEPROM)) coupled to the busfor storing static information and instructions for processor 714.

In addition, monitor 700 can include any of a variety of sensors suchas, but not limited to, medical-grade sensors which can be employed todetermine the health of the wearer. For example, the variety of sensorsmay include a temperature sensor (not shown) and an accelerometer 716for the x-axis, the y-axis and the z-axis, as shown in FIG. 8 and asdescribed in more detail below. Monitor 700 may also include a heartpulse sensor pair 718 coupled to band 704. In one embodiment, band 704may include a plurality of sensor pairs 718 coupled thereto to form asensor array 720. Sensor pairs 718 may be coupled to an inner surface722 of band 704 such that when monitor 700 is coupled to the user,sensor array 720 is positioned adjacent the user's skin, and morespecifically an artery of the user. Each sensor pair 718 may include anemitter 724 and a detector 726. In the exemplary embodiment, emitter 724may include a light source 728 such as a light emitting diode (LED),which facilitates emitting light, or an electromagnetic wave into theuser's body, as described in more detail below. Alternatively, lightsource 728 may be any type of light source known to a person havingordinary skill in the art that enables monitor 700 to function asdescribed herein. Detector 726 facilitates detecting the light emittedinto the user, which is reflected or refracted back from the user, asdescribed in more detail below. In one embodiment, detector 726 may be aphotodiode that causes varying amplitudes of current to flow in thecircuit in correlation with the user's blood flow. Alternatively,detector 726 may be any type of detector known to a person havingordinary skill in the art that enables monitor 700 to function asdescribed herein.

Each sensor pair 718 may be positioned adjacent another sensor pair 718coupled to band 704. Adjacent sensor pairs 718 may be oriented such thatemitter 724 of a first sensor pair 718 is positioned opposite fromdetector 726 of a second sensor pair 718 and detector 726 of the firstsensor pair 718 is positioned opposite from emitter 724 of the secondsensor pair 718. As a result, each sensor pair 718 is oriented in asubstantially opposite position with respect to each adjacent sensorpair 718.

FIG. 10 is a chart readout view of a signal 730 detected by detector726, as described in more detail below. Signal 730 includes peak datapoints 732 that generally represent the user's heart beats detected bydetector 726. The x-axis of the chart represents time; therefore adistance equivalent to the distance between two adjacent peak points 732generally represents the user's heart beat interval time 734. In oneembodiment, the user's heart rate is directly calculated into beats perminute; the variation between beats per minute may then be calculatedinto heart rate variability in the time domain. A Fourier Transform orsimilar technique may also be applied to the variation between beats perminute in order to transform the variation between beats per minute intothe frequency domain for spectral analysis. In another embodiment,external interference and/or factors may cause artifacts, orfalse-positive data points to develop in the signal. Artifacts may beinformation or peak points that do not represent the user's heart beatbut rather are caused by external factors. In one embodiment, externalfactors such as, but not limited to, overhead lights, fluorescent lightsand the user's motion may create artifacts in the received signal 730which may render signal 730 unreadable and unstable. Artifacts in asignal add additional peak points to the signal which monitor 700 maymistakenly confuse as a heart pulse. In such an example, if monitor 700treats an artifact as a heart beat, monitor 700 may report incorrectvital information of the user to system 100. As a result, such artifactsshould be reduced, eliminated, canceled out of the signal and/or ignoredfrom signal 730 by monitor 700, as described in more detail below. Inone embodiment, motional artifacts may be eliminated by taking a readingof the user's heart rate when the user is substantially still. Inanother embodiment, interference artifacts may be reduced by filteringout the known frequencies of common interfering devices such as overheadlights. In yet another embodiment, motional artifacts may be cancelledout using accelerometer 716, as described in more detail below

FIG. 11 is a logic flow diagram of heart rate code structure 736 formonitor 700, which enables monitor 700 to power on, detect, for example,peak points 732 within signal 730, filter signal 730 and send a filteredsignal to a heart rate algorithm 738, which facilitates determining theheart rate of the user. FIG. 12 is a schematic view of monitor 700. FIG.13 is a logic flow chart of heart rate algorithm 738, which facilitatesdetecting, for example, peak points 732 in signal 730, determining theuser's heart beat pulses and determining the user's heart rate.

Sensor array 720 enables monitor 700 to automatically adjust to the manydifferent physiologies of users that may wear monitor 700. As describedbelow, processor 714 determines which sensor pair 718 may detect anacceptable signal from the user. As a result, monitor 700 may be coupledto any type of wrist on any type of user and detect a heart beat signal.

In the exemplary embodiment, monitor 700 may be coupled to the user'swrist such that sensor array 720 is positioned substantially adjacentthe underside of the user's wrist, and more specifically the user'sartery. As described in more detail below, during operation, monitor 700facilitates detecting a user's heart rate by emitting light into theskin of the user using emitter 724. The light penetrates the skin and ispartially reflected or refracted back out of the skin towards detector726. When emitter 724 is positioned substantially near an artery of theuser, the pulsing of blood through the artery may selectively filter thefrequency of the reflected or refracted light, such that the reflectedor refracted light substantially represents the pulsing of the blood andtherefore the heart beats of the user. As a result, detector 726 maydetect the frequency-density changes in the reflected or refractedlight, which enables monitor 700 to detect the heart beats and the heartrate of the user, as described in more detail below.

During operation, heart rate algorithm 738 powers up monitor 700 at step740. Next, in step 742, heart rate algorithm 738 waits for stabilizationof readable signal 730, wherein processor 714 searches for a readablesignal 730 using sensor array 720. Stabilization of a received signaloccurs when a readable heart beat signal 730 is detected by detector 726and the heart beat signal 730 is substantially free of artifacts.Alternatively, processor 714 may use sensor array 720 to search for anoptimal signal. In searching for a readable signal, monitor 700 emitslight using emitter 724, wherein the light is reflected or refractedback towards monitor 700 and detected using detector 726 of one ofsensor pairs 718 as signal 730. Detector 726 may need to stabilize thebias control feedback loop prior to detecting reference peaks. In oneembodiment, a level of feedback may be used by monitor 700 to properlybias detector 726, which enables detector 726 to better distinguishvariations in signal 730. In such an embodiment, monitor 700 may have aset or previously programmed detector bias feedback value, which is readfrom memory 710 by processor 714 in step 744, shown in FIG. 11. Monitor700 then controls the detector bias feedback at step 745, which adjuststhe sensitivity of detector 726. Similarly, an intensity level, or powercontrol, of light source 728 may be adjusted by monitor 700 tofacilitate increasing the effectiveness of light source 728, asdescribed in more detail below.

In the exemplary embodiment, sensor array 720 may be coupled incommunication to an analog gain 746 that facilitates increasing theanalog signal before the signal is converted to a digital signal. Analoggain 746 may be coupled, in series, to an analog filter 748, ananalog/digital converter 750 and a digital filter 752. In oneembodiment, analog filter 748 may be a low pass filter. Analog filter748 may also be a filter having several stages, where the first stage isabout 15 Hz the second stage is about 20 Hz, and the third stage isabout 66 Hz. In one embodiment, digital filter 752 may be a band stopfilter or a notch filter that facilitates filtering frequencies at about60 Hz, at about 90 Hz and at about 120 Hz. As a result, analog filter748 and digital filter 752 facilitate removing and/or reducing ambientinterference from the detected signal 730.

Turning back to FIG. 10, once signal 730 is stabilized and read bymonitor 700, in step 754 heart rate algorithm 738, and more specificallyprocessor 714, facilitates determining a reference peak point 755, whichrepresents a reference heart beat of the user. The reference peak point755 enables monitor 700 to determine additional heart beats of the user,though other methods of setting a reference point may also beapplicable. In one embodiment, reference peak point 755 may be one of aset of potential peak points 732 within signal 730 that passes specificqualifiers, or factors, such as but not limited to, amplitude, and maybe the first to be observed in the sample. A peak point 732 that has anamplitude that falls within a certain range may be an acceptablereference peak point 755. In one embodiment, the amplitude range of peakpoints 732 may be measured in volts. In the event signal 730 is too weakand peak points 732 have too low an amplitude, monitor 700 mayautomatically adjust sensor pairs 718 to facilitate enhancing signal730. Monitor 700 may also adjust sensor pairs 718 in the event signal730 is too strong and peak points 732 have too high an amplitude. In thecase of a weak signal, monitor 700 may automatically increase theintensity of emitter 724 to facilitate strengthening the amplitude ofsignal 730 received by detector 726. Moreover, monitor 700 may modifythe detector bias feedback to strengthen the signal detected by detector726 to facilitate making signal 730 more readable. Similarly, monitor700 may decrease the intensity of emitter 724 to facilitate weakeningthe amplitude of peak points 732 to obtain a more readable signal 730.Moreover, monitor 700 may modify the detector bias feedback to weakenthe signal sensitivity of detector 726 to facilitate making signal 730more readable.

In the event the changing of the intensity of light source 728 orchanging the detector bias feedback does not produce a readable signal,monitor 700 may deactivate the current sensor pair 718 and activateanother sensor pair 718 of sensor array 720. Once the new sensor pair718 is activated, monitor 700 restarts the algorithm at step 742 andwaits for stabilization. As a result, monitor 700 may fit a variety ofusers that have wrists of differing circumference and shape.Furthermore, monitor 700 and more specifically sensor array 720 mayallow users to adjust the position of the band on their body without theneed for assistance from a third party to re-position monitor 700 andsensor array 720. Monitor 700 and specifically sensor array 720 may alsoself-align on the user's wrist, thereby facilitating obtaining animproved signal and facilitating obtaining a signal in the event ofmonitor 700 being moved or adjusted by the user. As such, monitor 700,and more specifically sensor array 720 enables monitor 700 to fitvirtually all users. In the event no readable signal can be found usingall the sensor pairs 718 of sensor array 720, monitor 700 may turn offat shutdown step 756.

Once an acceptable reference peak point 755 is detected, monitor 700saves the parameters of reference peak point 755 into memory 710. In oneembodiment, the parameters of reference peak point 755 may include, butnot limited to, amplitude. Next, in step 760 monitor 700 searches for asubsequent, or second, peak point 761 that passes specific qualifiers,such as a substantially similar amplitude as reference peak point 755and where second peak point 761 occurs within a specific time afterreference peak point 755. In the event monitor 700 detects a second peakpoint 761 that passes the qualifiers, second peak point 761 is saved inmemory 710 as a potential first heart beat peak point in step 762.Second peak point 761 is then used as a reference peak point to enablemonitor 700 to detect a third peak point 764 that passes the qualifierswith respect to second peak point 761. If third peak point 764 does notpass the qualifiers with respect to second peak point 761, then monitor700 goes back to step 754 to begin searching for a first reference peakpoint 755. In other words, if third peak point 764 does not have thesubstantially same amplitude as second peak point 761 and/or third peakpoint 764 does not occur within a predicted amount of time after secondpeak point 761, then second peak point 761 and/or third peak point 764may be an artifact and monitor 700 goes back to step 754 to restart thereference point process.

In step 766, if third peak point 764 passes the qualifiers, monitor 700saves the second and third peak points 761 and 764 as heart beats anddetermines the time between second and third peaks points 761 and 764 tofacilitate determining a first heart rate value 768. Moreover, monitor700 saves third peak point 764 as the new reference peak point andcontinues searching for a subsequent fourth peak point 770 and a fifthpeak point 772. Similarly, if fourth peak point 770 passes thequalifiers with respect to third peak point 764, fourth peak point 770is then saved into memory 710 and becomes the new reference peak pointfor fifth peak point 772. Moreover, processor 714 may then determine asecond heart rate value 774, which may be the time between third peakpoint 764 and fourth peak point 770.

In step 776, once forth and fifth peak points 770 and 772 are found,monitor 700 determines the time between forth and fifth peak points 770and 772 to facilitate calculating a third heart rate value 778, which issaved to memory 710. The first, second and third heart rate values 768,774 and 778 are then averaged together to determine an average heartrate for the user. As monitor 700 determines new heart rate values, theolder heart rate values are cleared out of the averaging formula. As aresult, the user's average heart rate is continually updated and theuser's heart rate variability is determined. Variation in heart rate mayalso be determined over various time spans and may utilize statisticalcalculations. Furthermore, variation in heart rate may be converted tothe frequency domain via utilization of Fourier Transforms, and theresults of the calculation may be sent to server 110.

In one embodiment, once monitor 700 determines the heart rate of theuser after detecting four uninterrupted heart beats, monitor 700 mayshutdown at step 780. Alternatively, monitor 700 may be programmed tocontinuously detect the user's heart rate. In yet another embodiment,monitor 700 may be programmed to monitor the user's heart rate for aspecific amount of time before shutting down. In such an embodiment,monitor 700 may also be programmed to restart after a specific amount oftime and detect the user's heart rate. In another embodiment, monitor700 may be programmed to monitor the user's heart rate for any amount oftime. Allowing such variation in sampling methods may facilitateextending battery life of monitor 700. In one embodiment, the sensorpair 718 that was used in the most recent successful measurement may beretained in memory such that it may be used first in the next samplesession, thereby shortening detection time and extending battery life ofmonitor 700.

Monitor 700 may transmit the user's heart rate and heart ratevariability to server 110 using wireless transceiver 712. In the eventmonitor 700 is out of range of server 110, or any of the othercommunication components of system 100, monitor 700 may save the heartrate information in memory 710. Such information may be uploaded toserver 110 once communication between server 110 and monitor 700 isrestored.

In the exemplary embodiment, monitor 700 facilitates detecting a heartrate of the user using an easy to use and adaptive watch. Monitor 700may be attached to any user's wrist and processor 714 will begin tosearch for a readable signal 730. Each user may have differentphysiologies, skin thicknesses, and wrist thicknesses to which monitor700, and more specifically, sensor array 720 may adapt. In oneembodiment, monitor 700 may be initially configured by a nurse or atechnician to adjust, or customize the various settings on monitor 700for the user and store those settings in memory 710. In such anembodiment, the various settings may be, but not limited to, theintensity level of light source 728, the detector bias feedback value ofdetector 726 and the particular sensor pair 718 that initially receivesa readable signal 730. In the event monitor 700 shifts on the user'swrist or if the user removes monitor 700 and then reattaches monitor700, monitor 700 may default to the custom settings in memory 710 tobegin the search for signal 730, which facilitates reducing the timerequired to detect a readable signal thereby increasing the battery lifeof monitor 700. In the event monitor 700 has been substantially shiftedon the wrist or reattached in a substantially different orientation thanthe initial orientation, monitor 700, and more specifically processor714, may begin the stabilization process to find signal 730 as describedabove.

In another embodiment, monitor 700 may be initially attached by a userto their wrist, without the use of a nurse or technician to customizemonitor 700. In such an embodiment, processor 700 may be programmed toinitialize sensor array 720 and begin the stabilization process asdescribed above. Monitor 700 may automatically adjust the settings ofmonitor 700, which may include but not limited to, the intensity oflight source 728, the detector bias feedback value of detector 726 andthe particular sensor pair 718. Once a readable signal 730 is found,monitor 700 may store the above-described settings into memory 710 tofacilitate faster stabilization of signal 730 in the event monitor 700is shifted on the user's wrist or removed and reattached in asubstantially different orientation on the user's wrist, therebyfacilitating quickly re-determining the user's heart rate after removaland reattachment.

FIG. 14 shows an alternative embodiment of monitor 700 that includesaccelerometer 716 coupled thereto. In the exemplary embodiment,accelerometer 716 facilitates measuring the acceleration, or motion, ofmonitor 700 in the x-axis, the y-axis and the z-axis. In the exemplaryembodiment, accelerometer 716 may be coupled to an adaptive filter 782,which may utilize the information gathered by accelerometer 716 tofilter undesirable heart rate artifacts due to motion.

During operation, motion of monitor 700 may create motional noise 784,which may transfer to signal 730, such that monitor 700 may detectmotional noise 784. Motional noise 784 may be transferred to signal 730such that a motional peak point generated by motional noise 784, may bea function of the motion. As a result, a transfer function 786 may beapplied to the motion to determine the value of the motional peak pointdetected in signal 730.

In one embodiment, accelerometer 716 may be used to cancel and/or ignoremotion artifacts in signal 730 that are created by the user's movements.For example, the movement of a user's arm as the user moves about maycreate pressure fluctuations in the user's blood flow, which may affectthe reflected or refracted light which affects signal 730 received bydetector 726. In one embodiment, accelerometer 716 may be used tomeasure the movement of monitor 700 and the movement of the user's limbto which monitor 700 is attached. Accelerometer 716 facilitates sensingand recording the movements such as, but not limited to, spatialposition, acceleration and velocity of monitor 700 and the user's arm.In step 788, as shown in FIG. 13, monitor 700, and more specificallyprocessor 714, may then match recorded motions with any received signalsreceived at the substantially same time by detector 726. In the event apeak point is found that does not pass the qualifiers and the peak pointwas detected at substantially the same time as the recorded movement ofmonitor 700 by accelerometer 716, the peak point may be declared amotional artifact and thus ignored by processor 714. As a result,processor 714 may continue looking for a subsequent peak point withouthaving to restart the heart rate algorithm 736, which facilitatesreducing time and increasing battery life when monitor 700 determinesthe heart rate of the user.

In the exemplary embodiment, accelerometer 716 enables monitor 700 todetect the heart beats and determine the heart rate and heart ratevariability of a user while the user is moving or walking. Motionalartifacts, or changes in the user's blood flow due to the user'smovement may be measured and ignored by heart rate algorithm 736. As aresult, the user is more free to move about while monitor 700 monitorsthe user's heart rate. Moreover, accelerometer 716 reduces the need formonitor 700 to restart the stabilization process as described above,which facilitates increasing the battery life of monitor 700.

In another exemplary embodiment, transfer function 786 may adjust signal730 in accordance with the amplitude and direction of the vector ofmotion. Adaptive filter 782 may also automatically approximate anunknown transfer function 786 and remove motion artifacts from signal730. Consequently, the number of acceptable signals for the heart rateand heart rate variability algorithm may be increased, and the need formonitor 700 to continue sampling or to restart the sampling process maybe reduced. This may also facilitate extending the battery life ofmonitor 700.

The foregoing description and accompanying figures illustrate theprinciples, preferred embodiments and modes of operation of theinvention. However, the invention should not be construed as beinglimited to the particular embodiments discussed above. Additionalvariations of the embodiments discussed above will be appreciated bythose skilled in the art.

Therefore, the above-described embodiments should be regarded asillustrative rather than restrictive. Accordingly, it should beappreciated that variations to those embodiments can be made by thoseskilled in the art without departing from the scope of the invention asdefined by the following claims.

1. A wearable sensor comprising: a timing mechanism; a plurality ofsensor pairs coupled to said timing mechanism wherein each sensor paircomprises an emitter and a detector; and a microcontroller coupled incommunication to said timing mechanism and said plurality of sensorpairs.
 2. A wearable sensor in accordance with claim 1 furthercomprising an accelerometer coupled to said microcontroller.
 3. Awearable sensor in accordance with claim 1 further comprising a bandthat facilitates coupling said plurality of sensor pairs to a user.
 4. Awearable sensor in accordance with claim 3 wherein said plurality ofsensor pairs are positioned in an array on at least one of said band andsaid timing mechanism.
 5. A wearable sensor in accordance with claim 1wherein said timing mechanism comprises a watch.
 6. A wearable sensor inaccordance with claim 1 wherein said emitter comprises a light emittingdevice.
 7. A wearable sensor in accordance with claim 1 wherein saiddetector comprises a photodiode.
 8. A monitoring system, comprising: atleast one wearable monitor coupled to a user, said at least one wearablemonitor comprising: a timing mechanism; a plurality of sensor pairscoupled to said timing mechanism wherein each sensor pair comprises anemitter and a detector; and a microcontroller coupled in communicationto said timing mechanism and said plurality of sensor pairs; at leastone gateway having a second transceiver; at least one device located ata remote location; and at least one server coupled in communicationusing a wide area network to the at least one gateway and the at leastone device, said at least one wearable monitor is coupled in wirelesscommunication to said at least one gateway, said plurality of sensorpairs facilitate sensing a heart rate of the user and transmit the heartrate to said at least one server.
 9. A system in accordance with claim 8further comprising a band that facilitates coupling said plurality ofsensor pairs to the user.
 10. A system in accordance with claim 9wherein said plurality of sensor pairs are positioned in an array on atleast one of said band and said timing mechanism.
 11. A system inaccordance with claim 8 further comprising an accelerometer coupled tosaid microcontroller, said accelerometer facilitates detecting movementof said wearable sensor.
 12. A system in accordance with claim 8 whereinsaid timing mechanism comprises a watch.
 13. A system in accordance withclaim 8 wherein said emitter comprises a light emitting device.
 14. Asystem in accordance with claim 8 wherein said detector comprises aphotodiode.
 15. A method of sensing a heart rate using a wearablemonitor that includes a timing mechanism, a memory, a plurality ofsensor pairs coupled to the timing mechanism wherein each sensor pairincludes an emitter and a detector, and a microcontroller coupled incommunication to the timing mechanism, the memory and the plurality ofsensor pairs, said method comprising: coupling the wearable monitor to auser; emitting an electromagnetic wave from the emitter into the user;receiving an electromagnetic wave signal from the user at the detector;stabilizing the electromagnetic wave; determining a first pulse;determining a plurality of subsequent pulses; calculating a heart rateof the user; and recording the heart rate of the user in at least oneserver.
 16. A method in accordance with claim 15 wherein stabilizing theelectromagnetic wave further comprises: filtering ambientelectromagnetic waves; and biasing the detector to facilitate receivinga readable electromagnetic wave signal.
 17. A method in accordance withclaim 15 wherein determining a first pulse further comprises: sensing afirst peak amplitude in the electromagnetic wave signal using a firstsensor pair; determining whether the first peak amplitude is acceptable;adjusting an electromagnetic wave emission level of the emitter in theevent the peak amplitude is not acceptable; sensing the first peakamplitude in the electromagnetic wave signal using a second sensor pairin the event the first sensor pair cannot sense an acceptable peakamplitude; recording a first acceptable peak amplitude in the memory ofthe wearable monitor; and recording the most recently used sensor pairin the memory of the wearable monitor.
 18. A method in accordance withclaim 17 wherein determining a plurality of subsequent pulses furthercomprises: sensing at least three subsequent peak amplitudes in thesignal using the same sensor pair that detected the first acceptablepeak amplitude, wherein each subsequent peak amplitude is within anacceptable range with respect to the preceding peak amplitude; andrecording the at least three subsequent peak amplitudes in the memory ofthe wearable monitor.
 19. A method in accordance with claim 18 whereincalculating a heart rate of the user further comprises: recording thetime between each peak amplitude to determine the instantaneous heartrate of the user; and averaging the recorded times between peakamplitudes to determine the average heart rate of the user.
 20. A methodin accordance with claim 19 wherein calculating a heart rate of the userfurther comprises: calculating statistical variation in heart rate overtime; using Fourier Transforms to transform variations in theinstantaneous heart rate of the user into a frequency domain forspectral analysis of heart rate variation.
 21. A method in accordancewith claim 15 wherein determining a first pulse further comprises:detecting movements of the wearable monitor caused by the movements ofthe user using an accelerometer that is coupled to the microcontroller;determining false-positive peak amplitudes that coincide with movementsof the wearable monitor detected by the accelerometer; and omitting thefalse-positive peak amplitudes from said step of calculating a heartrate such that the wearable monitor may sense the heart rate of the userwhile the user is moving.
 22. A method in accordance with claim 21wherein determining a first pulse further comprises: increasing theoccurrence of acceptable peak amplitudes by mathematically compensatingpeak amplitudes based on the amplitude and direction of the movements ofthe user.
 23. A health care monitoring system comprising: means foremitting electromagnetic waves into a user; means for receiving theemitted electromagnetic waves as a signal; means for determining aplurality of peak amplitudes within the signal; means for calculating aheart rate of the user; and means for recording the heart rate on atleast one server.
 24. A health care monitoring system in accordance withclaim 23 further comprising means for filtering ambient electromagneticwaves.
 25. A health care monitoring system in accordance with claim 23further comprising means for omitting false-positive peak amplitudes inthe signal caused by the movements of the user.
 26. A health caremonitoring system in accordance with claim 23 further comprising meansfor sensing the electromagnetic waves using a second sensor pair.
 27. Ahealth care monitoring system in accordance with claim 23 furthercomprising means for increasing the occurrence of acceptable peakamplitudes by mathematically compensating peak amplitudes based on theamplitude and direction of the movements of the user.